1. Field of the Invention
The embodiment relates to a liquid crystal display device and an inspection method thereof, and more particularly, to a liquid crystal display device and an inspection method thereof that are capable of detecting malfunctions.
2. Description of the Related Art
The liquid crystal display (LCD) device displays images by controlling light transmittance ratio of liquid crystal cells disposed in the form of matrix on a liquid crystal panel according to data signals. To achieve this, the liquid crystal display device includes a liquid crystal panel having liquid crystal cells and a drive circuit to drive the liquid crystal cells.
The LCD panel includes an upper substrate and a lower substrate. The upper substrate includes a red color filter, a green color filter and a blue color filter, and a black matrix formed between the color filters. A common electrode is formed on the color filters. The lower substrate includes thin film transistors (TFT) formed at each of the liquid crystal cells, pixel electrodes formed to be connected to the TFT, and wire electrodes formed to be connected to the TFT.
The liquid crystal panel is produced through a processing procedure, and goes through an inspection process to detect short and open of scan lines and data lines, and malfunctions of the liquid crystal cells after the completion of the liquid crystal panel. The liquid crystal panel includes a first shorting bar connected to each of the data lines and a second shorting bar connected to each of the scan lines for the inspection process. Short and open of lines of liquid crystal display device and malfunctions of the liquid crystal cells are detected with supply of fixed inspection signals to the first shorting bar and/or the second shorting bar.
Data transistors are formed between data pads, which supplies data signals to the data lines, and the first shorting bar. The data transistors are disposed on an overlapped area with data integrated circuits, electrically connect data pads with the first shorting bar in the inspection process, and electrically isolate the data pads from the first shorting bar in other processes. In the same manner, gate transistors are formed between the second shorting bar and gate pads, and electrically connect the gate pads with the second shorting bar during the inspection process.
On the other hand, the data transistors supply a signal with a predetermined frequency as the inspection signal to check an abnormality of the liquid crystal cells (i.e., lighting inspection), and are formed to have at least a predetermined channel width as the result. In this case, there is a disadvantage that the data transistors are not formed at the data integrated circuits, which are gradually downsized, and the overlapped area of the panel.
To overcome the disadvantage, the data transistors can be formed at outer areas which are not overlapped with the data integrated circuits. At this time, the data transistors are electrically connected to the data lines without passage of the data pads. However, in the event that the data transistors are directly connected to the data lines, there is a disadvantage that malfunctions of connection lines (i.e., fan-out part) between data pads and data lines is not detected.